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I'm looking for suggestions on experimenting with Calcium Acetate to feed bacteria in some kind of anaerobic and photosynthetic sump zone. My hypothesis is that a new class of bacteria can be utilized to maintain nutrients and supplement calcium. Apparently one of the risks would be O2 depletion in the water column so I'd imagine I could utilize my APEX for ORP and ozone control of the calcium effluent. I'm considering using a light from under the sump (if any of this makes sense)?

I am not sure that it'd work well as a proxy for an oxygen probe. I'm not sure what the status is for monitor dissolved oxygen content, but I think it'd be pricy. Is one of the goals supplement calcium and alkalinity? Vinegar would be fine for feeding bacteria, and it's very cheap. Calcium acetate makes a good, if sometimes expensive, calcium and alkalinity supplement. It'll fuel bacteria just as well, though.

If you'd like to use calcium acetate as a combination calcium supplement and carbon source to encourage denitrifying bacteria, there's no particular reason to purchase calcium acetate if it's expensive. You can simply combine vinegar and calcium hydroxide (kalkwasser) in the proper ratio, and viola - calcium acetate.

If what you mean by your post about a combination photosynthetic/anoxic refugium, that's actually pretty easy to accomplish - you simply use a 3 or 4 inch layer of sand in the refugium, and stock the water above the sand with macroalgae. The drawback to this sort of arrangement is maintenance - the sand will eventually become clogged with detritus, and one would pretty much have to completely disassemble the sump and start over when the sand layer became too clogged.

I'm sure I'm in way over my head in my attempt to answer so don't take this as fact. I'm assuming Aerobic anoxygenic phototrophic bacteria (AAPBs) at this point. I've read the only photosynthetic pigment that exists in AAPB is BChl a. AAPBs are currently classified taxonomically in 2 marine genera listed as, Erythrobacter and Roseobacter.

I'm sure I'm in way over my head in my attempt to answer so don't take this as fact. I'm assuming Aerobic anoxygenic phototrophic bacteria (AAPBs) at this point. I've read the only photosynthetic pigment that exists in AAPB is BChl a. AAPBs are currently classified taxonomically in 2 marine genera listed as, Erythrobacter and Roseobacter.

Those bacteria dont split water and use oxygen from it as the electron donor. So you need to dose whatever is as the primary electron donor as well. Most cases, sulfur is the electron donor and the end product is hydrogen sulfide, which can crash a tank.

If you'd like to use calcium acetate as a combination calcium supplement and carbon source to encourage denitrifying bacteria, there's no particular reason to purchase calcium acetate if it's expensive. You can simply combine vinegar and calcium hydroxide (kalkwasser) in the proper ratio, and viola - calcium acetate. . . .

Quote:

Originally Posted by dkeller_nc

. . .sand with macroalgae. . . .

Thanks for the sound advice. I think macroalgae, specifically chaeto is a very good probiotic solution to nutrient reduction with proper lighting (balanced par/spectrum) and tank flow. If this were a business decision I would indeed use it with miracle mud, a Kessil H380, and a calcium reactor. I've used the sump/DSB GFO method for years, and am very curious about how these bacteria would potentially be of benefit to Ph/Mg/Ca/Alk differentials.[/QUOTE]

Absolutely no plans to dose sulfer but have also just noticed the Korallin BioDenitrator S-1502 which really sounds like bad juju. I'm still leaning toward this experiment because traces of sulfer and other inorganic compounds may incidentally make there way into my system and out instead of accumulating for a decade. It is also an interesting medical fact that Calcium Acetate helps reduce phosphate levels in people with advanced kidney disease. It seems these bacteria are underexplored and I appreciate the caution.

An anaerobic and photosynthetic zone would be hard to accomplish. Photosynthesis produces a lot of oxygen. Is there a reason you'd like to area to be anoxic?

Just from a simple high level, anoxic areas are part of the oceans ecosystem to break stuff down that effects SPS growth and coloration where it could not otherwise be exported. I don't think it needs to be much more than clear acrylic beads increasing surface in a very low flow or protected area, perhaps receiving light from underneath and elevated acrylic sump.

Quote:

Originally Posted by bertoni

ORP is a complicated issue in an aquarium:

Ozone will be controlled by the apex to maintain a range of 350-400 mV at a rate of 50mg/hr. The frequency of ozone kicking on is what concerns me, e.g. ideally ozone would never kick on, or only briefly after feeding, etc.

I think you're interested in using a plenum or a deep sand bed, from what I understand. There's no need to feed calcium acetate to run a substrate for denitrification. I would use normal sand, because light shining through the substrate will encourage photosynthesis, which will add oxygen. "Aerobic anoxic" is a bit of a contradiction, since aerobic metabolism refers to the consumption of oxygen. Photosynthetic organisms produce oxygen, and they will grow given light and nutrients.

Setting ozone to a specific ORP can be quite dangerous, as tanks vary in the ORP levels naturally. What is the purpose of the ozone? If it's being used to break down organics, I would set the controller for it to a bit above the level seen without ozone, and work from there.

I think you're interested in using a plenum or a deep sand bed, from what I understand. There's no need to feed calcium acetate to run a substrate for denitrification. I would use normal sand, because light shining through the substrate will encourage photosynthesis, which will add oxygen. "Aerobic anoxic" is a bit of a contradiction, since aerobic metabolism refers to the consumption of oxygen. Photosynthetic organisms produce oxygen, and they will grow given light and nutrients.

Setting ozone to a specific ORP can be quite dangerous, as tanks vary in the ORP levels naturally. What is the purpose of the ozone? If it's being used to break down organics, I would set the controller for it to a bit above the level seen without ozone, and work from there.

I think the OP was talking about anoxygenic photosynthesis, like the types of photosynthesis done by purple sulfur bacteria, purple non-sulfur bacteria and heliobacteria.

But I agree with you that it would not be practical to cultivate these bacteria in an regular aquarium setting. They need to be on top of the sand bed and still need to be under anoxic conditions. So you need to deoxygenate the water going into their "environment" and reoxygenate the water going back into that tank from there (so to not suffocate the tank). Maybe effluent from a deep sand bed reactor can be used for deoxygenated water and it can be oxygenated afterwards using the skimmer. But still it would cause a "swampy" odor , since most of them oxidize either sulfur or ,to some lesser extend, methane, H2 or iron containing compounds.

On top of that these organisms either live in deep water with poor agitation or in surface of thermal water. For deep water ones,optimum light wavelength for photosynthesis is different from regular photosynthesis and the ones living in shallow water are thermophilic.

I agree that there are phototrophic organisms that don't produce oxygen. I apparently didn't use the term "photosynthetic" quite properly. Sigh! I agree that growing them would be difficult, and I'm not sure why this would be desirable. Are you sure that deoxygenating the water would be enough to prevent the growth of oxygen-producing photosynthetic organisms? I wasn't clear on that. I am not an expert in biology, by any means.

I agree that there are phototrophic organisms that don't produce oxygen. I apparently didn't use the term "photosynthetic" quite properly. Sigh! I agree that growing them would be difficult, and I'm not sure why this would be desirable. Are you sure that deoxygenating the water would be enough to prevent the growth of oxygen-producing photosynthetic organisms? I wasn't clear on that. I am not an expert in biology, by any means.

I think most eukaryotic photosynthetic organisms would not be able to live in an anoxic environment. I am at least sure that plants cannot live in anoxic conditions. So uni and multicellular algae might be avoided, as long as the flow of deoxygenated water is adequate enough to prevent accumulation of oxygen. There are some completely anaerobic eukaryotas that have reduced mitochondria or dont have one, but I dont know if any are photosynthetic.

But I think cyanobacteria would be able to live since they were the organism that oxygenated the earth starting from an anoxic planet. Thats why it would also be necessary to use different wavelengths that are suitable for organisms doing anoxygenic photosynthesis but not for Cyano. Or the tank can have its own hot spring with thermophilic bacteria .

I mean the amount of effort and equipment that would be invested in such a project can be used to built a more effective system ans safer, like a large deep sand bed reactor or a algae reactor.

I think what is making me skeptical is the idea that the substrate pore water can be kept anoxic. The flow through the media would have to remove a lot of oxygen to keep the sandbed from supporting oxygen-producing organisms. I think most organisms will produce more oxygen during the lighted period that they will consume during the dark period, but I might be wrong.

I think what is making me skeptical is the idea that the substrate pore water can be kept anoxic. The flow through the media would have to remove a lot of oxygen to keep the sandbed from supporting oxygen-producing organisms. I think most organisms will produce more oxygen during the lighted period that they will consume during the dark period, but I might be wrong.

They do, there will be an output of O2. But they dont have good mechanisms to scavenge the produced oxygen (since its normally not required). With ambient O2 being very low, it will just diffuse outside of the cell.

There will be oxygen there but the concentration would be very low to sustain cellular respiration respiration. Diatomic oxygen is uncharged and small, it would easily pass through the cell membranes and diffuse outside. Since the environment around them is also anoxic, it would probably oxidize something and will be lost. Also oxygen production would only happen if there is light,. With a regular day light cycle, they wont survive the night even, if intercellular oxygen generation during light period is enough.

All these stuff we discussed is why it is not a good idea. Such a system would require considerable management and stability. There is a reason why anoxygenic photosynthesis is very rare. It is advantageous to oxygenic photosynthesis only under very specific conditions, mostly under extreme environments. I mean everything aside, I doubt these organism would even be readily present in a tank, even if you built the system. You would probably need to buy and seed them.

I think you're interested in using a plenum or a deep sand bed, from what I understand. There's no need to feed calcium acetate to run a substrate for denitrification. I would use normal sand, because light shining through the substrate will encourage photosynthesis, which will add oxygen. "Aerobic anoxic" is a bit of a contradiction, since aerobic metabolism refers to the consumption of oxygen. Photosynthetic organisms produce oxygen, and they will grow given light and nutrients.

Setting ozone to a specific ORP can be quite dangerous, as tanks vary in the ORP levels naturally. What is the purpose of the ozone? If it's being used to break down organics, I would set the controller for it to a bit above the level seen without ozone, and work from there.

I have an external skimmer which leaves the first sump chamber available for high flow applications, and the second for low flow. You'll also notice the acrylic sump is elevated to faciliate a light underneath. Yes, I'm thinking plenum in low flow chamber . . :

The lab is set using an AquaC E180 driven by and Iwaki RLT 30 on 30G frag tank.

Okay, a plenum might be worth a shot. I'm having trouble visualizing the size here, but I might go for a deep sand bed. Plenums can cause problems, especially if some animals gets into the chamber and starts digging.

At this point I'm still waiting on ORP to baseline in and have decided on 1/4" firepit glass as substrate found on amazon. I've decided to forgo the plenum in the trigger sysems refugium as there is a manageable upward flow toward the return chamber as opposed to random display tank like dsb flows. I will post progress.

I went with a cyan colored glass substrate for the anoxic/phototrophic zone and will post pics. Seems to be working fine, have been growing out an acropora frag, mini carpet, and just added a bubble tip along with an orchid dottyback, cinnamon clown and two astrea snails. I haven't added the ozone yet as I have not found an ORP ceiling having just hit a new high of 380 yesterday. I use the brightwell Kalk+ which is comprised of Ca, Mg, and Sr hydroxide powder which I disolve straight into distilled vinegar and dose based on tank appearance. There are 0 Nitrates and phosphates in the water column. The water params have Alk elevated to 13dKH without any Ca precipitation onto pumps. My biggest problem at this point is having a completely unused 1000ml of rowaphos sitting on a shelf, and a lack of coral livestock. I'm looking for a nice pink Seriatapora online vendor? I'll have pics up in an hour or two.